Numerical transient modelling of the fouling phenomena and its influence on thermal performance in a low-scale biomass shell boiler

Abstract Biomass has been used as a fuel throughout history because of its abundance and the ease of obtaining it from nearby environments. Its use has been increasing in recent decades because it is considered a renewable energy source. However, the heterogeneity of its physical properties and chemical composition can cause major problems that hinder its use in thermal systems. Such problems are mainly slagging phenomena in beds, fouling of the main thermal-exchange surfaces and emission of particulate matter, with the last problem being closely linked to the first two. In the present work, modelling and simulation of combustion in a low-power biomass shell boiler will be approached. At the same time, the phenomena involved in the fouling of the exchange surfaces will be modelled, and their impact on the performance will be calculated. The modelling of the fouling phenomena in this boiler, in conjunction with the EBiTCoM (Eulerian Biomass Transient Combustion Model) developed by the Energy Technology Group of the University of Vigo, will produce a detailed view of the problematic areas of the system. From these models, preventive actions can be anticipated to avoid or greatly delay the drop in global efficiency, reducing emissions and the overall operating cost.